Question

what is the problem this the next program in Scheme which solve the problem of Hanoy’s tower

(define tower_of_hanoi
  (lambda (move discs from to using)
    (if (> discs 0)
        ((tower_of_hanoi move (- discs 1) from using to)
        (tower_of_hanoi move (- discs 1) using to from)))))

(procedure application: expected procedure, given: #void; arguments were: #void)

Thank u all.

Answer 1

In your code you were calling two function calls in (). When you use that your symbol need to be a function/procedure. So you got the error.

Check the code below. I changed it to (and

(define tower_of_hanoi
  (lambda (move discs from to using)
    (if (> discs 0)
        (and (tower_of_hanoi move (- discs 1) from using to)
             (display move)(display " from ")(display from) (display " to ")(display to) (display "\n")
             (tower_of_hanoi move (- discs 1) using to from)))))